The use of piezoelectric ceramics to provide continuos motion is well known. In other designs, such as the “Inch Worm” motor, for example, described in U.S. Pat. No. 4,847,979 issued Oct. 17, 1989, a mechanism is disclosed capable of some similar attributes most notability the ability to translate motion from a piezoelectric actuator to movement of an object. Also one might note that there is a required set of electrical steps to achieve this motion. The motion translated to the object is in direct proportion to the movement of the piezoelectric actuator. Since a piezoelectric stack actuator generally moves 0.0004″ to 0.0012″ it requires many electrical cycles to get movements of any sizeable amount. Some applications require various different relationships of speed, accuracy, and force beyond the above-described invention.
In another design such as “Ceramic Motor”, for example, described in U.S. Pat. No. 6,064,140 issued May 16, 2000, a mechanism is disclosed with four actuators operating near or in resonant mode. The above system then again lacks the ability for the different relationships of speed, accuracy, and force to be met and has a limited scope of applications.
In another design, such as “Three Axis Control For Machine Tool”, for example, described in U.S. Pat. No. 5,558,557 issued Sep. 24, 1996, a mechanism is disclosed with multiple actuators operating with a complex mechanical assembly in three axis to control a machine tool table to obtain a precise mechanical motion. This device requires many components, sensors, and complex control to obtain this function.
In another design, such as “E-Block Head Stack Microactuator Assembly”, for example, described in U.S. Pat. No. 6,025,975 issued Feb. 15, 2000, a mechanism is disclosed with a single actuator operating a simple mechanical assembly in a single axis to control a transducing head of a disk drive to obtain a precise mechanical motion. This system has a simple structure; its movement is only in one axis.
In another design, such as “Hermetic Compressor For Refrigeration Systems”, for example, described in U.S. Pat. No. 6,004,115 issued Dec. 21, 1999, a mechanism is disclosed with many actuators with the purpose of compressing a fluid. This system differs in that the piezoelectric actuators are directly in contact with the medium to be compressed or pumped and no provision was made for tolerance issues with the piezoelectric actuator.
In another design, such as “Linear Motor Driving Device”, for example, described in U.S. Pat. No. 4,736,131 issued Apr. 5, 1988, a mechanism is disclosed with multiple actuators operating with arm assemblies in two axis to create a linear motion. Then again this system does not have a single base structure manufactured at the same time to reduce the tolerance stack up associated with multiple components as it relates to actuators with small movements.